I've never used a plastic one; my Tech Armor ballistic glass protector feels like the S5 glass screen. But it has one HUGE advantage (besides the scratch protection) - it's very very resistant to smudging from skin oil on your fingertips. (The Zagg glass protectors are really bad in this regard.) On another S5 forum a user noted that he's a mechanic and is surprised at how well the Tech Armor resists smudging.
Just to reiterate what others have said, they are absolutely worth it. I wouldn't, however, go spend $40 on one of the more expensive brands. The $10-$15 protector I got (luvvitt) does just fine and then some.
Yes absolutely worth it. The feel is so much better. Your fingers will glide across the screen instead of dragging across. They don't have that tacky feel of plastic. I have a Spigen glasstr on mine.
It all depends on how well you handle your phone. I was thinking about getting a screen protector. But I handle my phones pretty well so I just use the plastic protector.
I got the glass screen protector for my brand new Samsung Galaxy S5 and I love it! I forget that I even have a screen protector on my phone! From here on out, I'll always go glass instead of plastic! Way better feel and better protection!
I think the glass screen protectors just feel better. My fingers drag across plastic screen protectors, but glass screen protectors feel like the real screen.
I have the ZeroLemon glass screen protector. I think it was $10 on Amazon. I love it. I will never go back to a plastic screen protector again. I just wish there was a smaller protector for the rear camera.
I don't know if I've been lucky or what, I've never used a screen protector and every phone I've used that has one drives me crazy. Someone told me I should get one of these glass ones but to be honest I don't see the need. I have two kids and am not super easy on my phone, so to each their own.